A Halachic Study of the Defect of the Covenant

Shalom Rabbi, during my years in the yeshiva I encountered many lessons about the defect of the covenant, but none of them were halakhic, and in particular not theoretical. Beyond the fact that yeshivahs only address this from a religious perspective, etc., I am not even talking about just a halakhic concern with the question of what the source of the prohibition is. My question is, are there good sources for Talmudic study on this subject. A question that occurred to me in the past, for example, is a married man who contemplates his wife, and even ejaculates in vain because of it, subject to a prohibition? Is this more than the prohibition of ejaculation outside the body during sexual intercourse? And if it is prohibited, is this prohibition similar to contemplating foreign women? And perhaps it can also be divided into whether or not his wife is niddah at the time of contemplation, etc.
I would love your thoughts.